1. Field of the Invention
This invention relates to a sheet feeding device, and more particularly to an improvement in such a device taking a sheet coated with an airtight material on the surface thereof.
2. Description of the Prior Art
For the purpose of producing hard copies of color pictures projected on a display screen of a CAD/CAM system, a thermal transferring printer or an inkjet printer is used. However, there are some problems with these techniques. It takes long to print out a picture, and only one color can be presented per dot so that the area of one picture element is large, therefore, the pictures printed are rough and not of the resolution.
In order to solve the above problems, another approach shown in U.S. Pat. No. 4,399,209 was proposed. A color imaging system that forms images by image-wise exposing a layer containing coloring precursors and a plurality of photosensitive compositions encapsulated in a layer of pressure rupturable microcapsules. The microcapsules are broken after putting then upon an image-receiving sheet applied with a developing material on the surface thereof, and the developing material reacts with the coloring precursors encapsulated in the ruptured microcapsules so that a predetermined image is transferred from the imaging sheet onto the image-receiving sheet. This imaging system seeks to present picture elements having the same size as those of the microcapsules. Therefore, color pictures can be printed with extremely high resolution.
However, there have been problems such that, since a powder developer is coated on the surface of the image-receiving sheet, the image-receiving sheet is scratched by a sheet feeding roller when it is taken out from a cassette causing the peeling off of the developing material, which not only deteriorates the picture image quality, but also causes duplicate sheets to be supplied because the sheet becomes difficult to slide due to the friction between the sheets.